Personally, I figure I'm not intelligent enough to research hard problems and I lack the social skills to be an activist, so by process of elimination the best path open to me for doing some serious good is making some serious money. Admittedly, some serious student loan debt also pushes me in this direction!
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
(I plan to make these threads from now on. Downvote if you disapprove. If I miss one, feel free to do it yourself.)